ace-of-base/190701programming_question.txt

The coding challenge is to create a small and simple database-like program. The
challenge consists of four tasks. You are not required to complete all four
tasks but you should do enough for us to be able to see the level and style of
your coding ability. The main things we are evaluating with this problem are
architecture design and your problem solving abilities.

Ruby is preferred.You can use the standard library but do not use external
libraries. We are keen to see how you code to solve a problem.  Do not use
sqlite or any other database engines so we can fully assess your abilities for
this role.


1.) Importer and Datastore

    You will be provided with a pipe separated file in the following format.

    File Sample:

        PROJECT|SHOT|VERSION|STATUS|FINISH_DATE|INTERNAL_BID|CREATED_DATE
        the hobbit|01|64|scheduled|2010-05-15|45.00|2010-04-01 13:35
        lotr|03|16|finished|2001-05-15|15.00|2001-04-01 06:47
        king kong|42|128|scheduled|2006-07-22|45.00|2006-08-04 07:22
        the hobbit|40|32|finished|2010-05-15|22.80|2010-03-22 01:10
        king kong|42|128|not required|2006-07-22|30.00|2006-10-15 09:14

    Field Descriptions:

        PROJECT: The project name or code name of the shot. (Text, max size 64 char)
        SHOT: The name of the shot. (Text, max size 64 char)
        VERSION: The current version of the file. (Integer, between 0 and 65535 inclusive)
        STATUS: The current status of the shot. (Text, max size 32 char)
        FINISH_DATE: The date the work on the shot is scheduled to end. (Date in YYYY-MM-DD format)
        INTERNAL_BID: The amount of days we estimate the work on this shot will take. (Floating-point number, between 0 and 65535)
        CREATED_DATE: The time and date when this record is being added to the system. (Timestamp in YYYY-MM-DD HH:MM format)

    Your first task is to parse and import the file into a simple datastore. You
    may use any file format that you want to implement to store the data.
    Records in the datastore should be unique by PROJECT, SHOT and VERSION.
    Subsequent imports with the same logical record should overwrite the earlier
    records.

2.) Query tool

    2.1) select, order and filter

        The next task is to create a query tool that can execute simple queries
        against the datastore you created in step one. The tool should accept
        command line args for SELECT, ORDER and FILTER functions.

        Example:
            $ ./query -s PROJECT,SHOT,VERSION,STATUS -o FINISH_DATE,INTERNAL_BID

            lotr,3,16,finished
            king kong,42,128,not required
            the hobbit,40,32,finished
            the hobbit,1,64,scheduled

            $ ./query -s PROJECT,SHOT,VERSION,STATUS -f FINISH_DATE=2006-07-22

            king kong,42,128,not required

    2.2) group and aggregate functions

        The next step is to add group by and aggregate functions to your query
        tool.  Your tool should support the following aggregates:

            MIN: select the minimum value from a column
            MAX: select the maximum value from a column
            SUM: select the summation of all values in a column (Only supported for number types)
            COUNT: count the distinct values in a column
            COLLECT: collect the distinct values in a column

        Example:
            $ ./query -s PROJECT,INTERNAL_BID:sum,SHOT:collect -g PROJECT

            the hobbit,67.80,[1,40]
            lotr,15.00,[3]
            king kong,30.00,[42]


    2.3) advanced filter function

        Add a filter function which evaluates boolean AND and OR expressions in
        the following format:

            PROJECT="the hobbit" AND SHOT=1 OR SHOT=40

        Assume AND has higher precedence than OR. Parentheses can be added to
        change the above statement to the more logical:

            PROJECT="the hobbit" AND (SHOT=1 OR SHOT=40)

        Example:
            $ ./query -s PROJECT,INTERNAL_BID -f 'PROJECT="the hobbit" OR PROJECT="lotr"'

            the hobbit,45.00
            lotr,15.00
            the hobbit,22.80